In standard computer memory (random access memory or RAM), the user supplies a memory address and the RAM returns the data word stored at that address. In content-addressable memory, or CAM, the user supplies a data word and the CAM searches its entire memory to see if that data word is stored anywhere therein. If so, the CAM returns a list of the storage address(es) where the word was found (and in some architectures, it also returns the data word, or other associated pieces of data).
Binary CAM is the simplest type of CAM; it employs data search words including only ones and zeroes. Ternary CAM (TCAM) allows a third matching state of “don't care” for one or more bits.